Through the studies outlined in this application we hope to explore alterations in glycoprotein formation, structure and function in transformed and malignant cells. Emphasis will be placed on further investigation of a distinctive galactosyltransferase (designated galactosyltransferase isoenzyme II, GT-II) associated with both clinical malignancy and in vitro transformation. Both GT-II and a normal galactosyltransferase isoenzyme (GT-I) have been purified to homogeneity. We will explore amino acid sequence and carbohydrate chain structure determinations on the purified isoenzymes. We hope to produce antibodies to human GT-I and GT-II to permit development of a more widely applicable assay as well as in situ localization of GT-II in the transformed cell. Studies with CEF infected with a temperature sensitive RSV should provide important data on the relationship of GT-II production (and secretion) to biological transformation as well as the isolation of the natural substrate of this enzyme. We will continue our studies of a previously described cancer-associated glycopeptide which serves as a cancer-associated galactosyltransferase acceptor (CAGA). This glycopeptide has been detected in sera of patients with extensive metastatic cancer. Purified CAGA specifically inhibits growth of transformed cells in culture and causes reduction of tumor growth in animal models. We will explore the kinetics of CAGA attachment to transformed cells using tritiated CAGA. The mechanism of the CAGA effects in vitro will be assessed by evaluation of glycoprotein composition and synthesis in transformed (CAGA-sensitive) and non-transformed (CAGA-insensitive) cells. Development of various animal tumor models will be undertaken to determine the pharmacokinetic characteristics of CAGA, its mechanisms of tumor growth inhibition and its potential use as an antineoplastic agent. Thus, a comprehensive study of the cancer-associated glycosyltransferase (GT-II) and the glycopeptide (CAGA) is proposed to enhance our understanding of the contribution and role of glycoproteins to transformed phenotype.